The report has brought the controversy surrounding the presidential candidate's emails, which has been rumbling on in the background, back into the limelight.

Donald Trump and other high-profile Republicans have suggested that Mrs Clinton acted criminally in conducting government business exclusively on a private account and initially failing to turn over her emails to the state department.

The report released on Wednesday did not go that far, but it did say that she acted improperly.

"At a minimum, Secretary Clinton should have surrendered all emails dealing with department business before leaving government service and, because she did not do so, she did not comply with the Department's policies that were implemented in accordance with the Federal Records Act," it says.

An FBI investigation into whether she placed US secrets at risk is ongoing.

Wow, 30,000 e-mails were deleted by Crooked Hillary Clinton. She said they had to do with a wedding reception. Liar! How can she run?

The report raises fresh concerns as to whether that information could have been vulnerable.

An aide to Mrs Clinton tasked with overseeing the server notified her staff in a January 2011 email that he had shut down the server because, "someone was trying to hack us and while they did not get in i didnt [sic] want to let them have the chance to".

The report also found that a senior aide to Mrs Clinton has asked her whether she would like to set up a government account, as some emails from her were apparently ending up in employee's spam folders.

“We should talk about putting you on state email or releasing your email address to the department so you are not going to spam," Huma Abedin, the aide, wrote.